Parasympathetic nervous drugs acting

Drugs Acting on the Sympathetic Nervous System 84 Drugs Acting on the Parasympathetic Nervous System 102 Nicotine 112 Biogenic Amines 116 Vasodilators 122... 

Cholinesterase inhibitors have less marked effects on vascular smooth muscle and on blood pressure than direct-acting muscarinic agonists. This is because indirect-acting drugs can modify the tone of only those vessels that are innervated by cholinergic nerves and because the net effects on vascular tone may reflect activation of both the parasympathetic and sympathetic nervous systems. The cholinomimetic effect at the smooth muscle effector tissue is minimal since few vascular beds receive cholinergic innervation. Activation of sympathetic ganglia may increase vascular resistance. 

Colonic transit time is only slightly affected by food but is reduced under stress. Studies have shown that drugs that act on the parasympathetic or sympathetic nervous system affect the propulsive motor activity, thereby influencing the colonic transit time. " Although not significantly affected by most disease, " the transit time is shorter in patients who complain of diarrhea and longer in patients with constipation. 

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